Technological advancements for efficient and economical production of energy and fuels from more sustainable resources than fossil fuels is an important goal for scientists and engineers. Biomass is well known as an abundant potential source of fuels and specialty chemicals. When biomass materials are subjected to thermal treatment, such as in pyrolysis processes, the liquids/vapors generated comprise oxygenated molecules, which are directly released from the biomass as it is thermally decomposed. Other polynuclear aromatic molecules can be formed from cross-interactions of the nascent molecules at the biomass/vapor interface and in the vapor phase. It is known that large biomass particles as well as long residence times enhance these side reactions and the fuel oil products produced contain larger molecules at a given thermolysis operating reactor temperature. To that effect, the operating parameters need to be optimized for a given kind of biomass material to minimum liquid hydrocarbon oxygen content, obtain the maximum oil yield, and minimum gas and coke yields.
Petroleum-based resources are currently a primary source of chemicals and transportation fuels. However, because of various factors including the finite reserves of petroleum, their unequal geographic distributions, and the environmentally motivated desire to decrease CO2 emissions, renewable energy sources, such as lignocellulosic biomass, have become promising candidates for the production of renewable fuels and chemicals. To use these abundant resources effectively with existing infrastructure, these highly oxygenated feedstocks must be chemically converted into products that are more stable and more similar to currently used fuels and chemicals. Catalytic fast pyrolysis is a thermochemical method that has been studied as potentially scalable process to convert solid biomass feedstocks into high energy density liquids or chemical platform molecules. It has been shown that the addition of a catalyst in a pyrolysis reactor enhances control over the product distribution through selective conversion of the vapor phase products into hydrocarbon products. It has been found that HZSM-5 has a high selectivity to aromatics and a gasoline range hydrocarbon, but is not selective for the production of oxygenated chemicals. Furthermore, large quantities of water and coke are typically observed with the use of HZSM-5 resulting in its own deactivation.
Accordingly, there is a need for an improved method for converting biomass into more useful chemicals. There is also a need for improved zeolite catalysts that generate less during catalytic fast pyrolysis of biomass.